Within the world of Aikido a variety of styles exists. The major ones include Aikikai, Yoshinkan
Yoseikan, Shodokan Aikido, Ki Society and Iwama. Aikikai is a style led by O-sensei's decendants and remains to be the largest Aikido organization.
Meanwhile, Yoshinkan was founded by Gozo Shioda and is known for its rigid practice of being precise or accurate. The Shodokan Aikido use to train with sparring and rule based competitions. The Ki Society in the meantime focuses on special training or programs for developing the ki. The Iwama style gives more attention to integration of weapon and barehand techniques. These are just a few of the major schools of Aikido. Let us focus on one: the Yoshinkan style.
Gozo Shioda, like most of the founders of the major Aikido schools, was a student of O-sensei or Morihei Ueshiba, the founder of Aikido. Most of the students of O-sensei built their own schools of Aikido based on their understandings on the teachings and basic principles of Aikido that O-sensei taught them.
Shioda's Aikido Yoshinkan focuses on the basics of Aikido. The six basic movements or the kihon dosa are taught repeatedly to Yoshinkan students. Students of this style spend a considerable time of their training regimen repeating basic movements in Aikido techniques.
However, outside observers sometimes view Yoshinkan Aikidokas or those that practices Aikido as having too automatic or too rigid movements because of their strict adherence to the techniques and in the correct execution of each movement.
This is why Yoshinkan is sometimes referred to as the "hard-style". Yoshinkan Aikidokas will practice the basics in the form of solo movements called kata. Nevertheless, as Yoshinkan Aikidokas gain more experience, their movements become more fluid and will eventually develop spontaneity of techniques.
Another distinguishing factor in Yoshinkan is the positioning of the Aikidoka's feet and hips. In other Aikido styles, the Aikidoka would position their body in such a way that the front foot is pointing straight forward while the back foot is at 90 degree angle to the front.
The hips meanwhile are a bit to the side. This position is called kamae. For Yoshinkan Aikidokas on the other hand, the basic or normal stance involves square hips with the front foot angled slightly out.
Training under the Yoshinkan Aikido means repeatedly practicing some 150 basic techniques until you get exactly the correct execution of each movement or technique. Mastering each and every technique will lead Aikidokas to master the remaining 3,000. Unlike other styles, Yoshinkan does not study any weapon forms and only practices with weapons as part of the Aikido's open hand techniques particularly in the areas of defense movements against weapon bearing opponents. Also, Yoshinkan Aikido does not participate in competitions. The focus of Shioda's Aikido is self defense.
It was Robert Twigger who made Yoshinkan Aikido popularized through his book Angry White Pyjamas. Twigger, a British travel writer and adventurer, detailed in his book the strict and more often gruesome training course that he had to endure when he signed up to an 11-month program intended to train Yoshinkan instructors.
Twigger's description of rigorous and agonizing training routines earned him a whole bunch of criticisms from the martial arts community. Nevertheless, he did receive some praise for relaying the realistic view of his experience with Yoshinkan Aikido.